fun main(){
val s1=student("李铜旺",20,1,"男")
val s2=student("韩春宝",20,2,"男")
val s3=student(
    "张三",
    22,
    3,
    "女"
)
val s4=s1.copy(name="李四")
// 解构
val (id,name)=s1
println("s1 :学号 ${id} 姓名 ${name}")
println(s1)
println(s2)
println(s3)
println(s4)
}
data class student(
    var name:String,
    var age:Int,
    var id:Int,
    var gender:String
)